In recent years, with the development of the display technologies, various kinds of display devices have been pushed into the market. For example, liquid crystal display device, organic light-emitting display device and the like have already become the leading products in the current display industry, in which the organic light-emitting display panel is the dominant trend of the display industry due to its excellent characteristics of light and thin, low power consumption, high brightness, high contrast, high definition, wide angle of view etc., and is the hot spot of researching in the display field.
One of the most important components of the organic light-emitting display panel is the organic light-emitting diode. The organic light-emitting diode emits light through the light-emitting layer between the anode and the cathode under driven of the electric field applied between the anode and the cathode. In a conventional organic light-emitting diode, since the hole mobility is generally higher than the electron mobility, the recombination center of the holes and the electrons will deviate from the light-emitting layer, resulting in that the luminous efficiency of the light-emitting layer decreases. Therefore, how to improve the electron mobility and further balance the mobility of the holes and the electrons in the organic light-emitting diode so that their recombination center will not deviate, without affecting the luminous efficiency of the OLED, is the most urgent problem to be solved.